This invention relates generally to the field of transfer and containment systems and, more particularly, to a vent pipe fitting for use with hydrocarbon fuel piping systems.
A substantial number of the leaks in underground storage systems, such as those utilized by hydrocarbon fuel dispensing stations, can be traced to the failure of underground piping systems utilized in the storage systems. These failures often occur at specific locations, such as at fittings (e.g., unions, elbows, couplings, and connections to underground equipment) and at corroded sections of metal pipes. Moreover, structural failures in piping systems sometimes occur when movements take place in tanks and/or piping systems because of high water tables or settling ground movement. This is particularly true in the case of rigid fiberglass piping systems, which are subject to cracking or outright structural failure.
In an effort to remedy these problems, secondarily contained piping systems were developed. Such a system often comprises containment chambers housing the various pieces of equipment. Primary conduit connects the equipment to allow a primary substance, referred to hereinafter as the product, to be communicated therebetween. Furthermore, a secondary conduit or wall (hereinafter generally referred to as xe2x80x9csecondary conduitxe2x80x9d) generally surrounds the primary conduit for containing any of the product that might escape the contained portion of the primary conduit.
According to one application, secondarily-contained piping systems can be utilized to prevent or decrease the inadvertent escape of hazardous fluids, such as hydrocarbon fuel, into the surrounding environment. Moreover, these systems often allow any escapage from the primary conduit into a space between the primary conduit and the secondary conduit to be removed without contaminating the surrounding environment. In some applications, secondarily-contained piping systems can also allow for the replacement of the primary conduit without excavating or breaking ground at the installed underground storage site.
In most applications, couplings are used to connect the respective ports of the various pieces of underground equipment (e.g., pumps, dispensers, etc.) to the ends of the primary conduit. Typically, the ends of the secondary conduit will be open to the containment chamber(s) so that the product can escape into or out of a space between the secondary conduit and the primary conduit from or to the containment chamber. Alternatively, the ends of the secondary conduit can also be sealed to contain any of the product which escapes from the contained portion of the primary conduit.
In some applications, it is also useful to contain and/or distribute a secondary substance associated with the product. For example, additional hazardous fluids, such as hydrocarbon fuel vapors, might be associated with the product. Conventionally, these secondary substances, referred to hereinafter, by example, as vapor, have been contained and/or distributed through separate conduits, referred to hereinafter as vapor lines, which may or may not be contained by the secondary conduit or wall.
Typical vapor lines are inflexible and are formed from rigid materials such as fiberglass and polyvinyl chloride (PVC). As previously mentioned, these vapor lines are often susceptible to cracking and/or outright structural failure. Conventional vapor lines also typically use metal fittings which must be attached to the vapor lines using materials such as epoxy. In cold weather, for example, heat blankets or packs must often be used when joining such a fitting to the vapor line in order to properly cure the bonding and/or sealing materials.
Accordingly, it would be advantageous to provide an improved containment system. In addition, it would be desirable to provide an improved fitting for use in a containment system. Moreover, it would also be advantageous to provide a secondarily contained piping system that is capable of containing and/or distributing secondary substances, without necessarily including a separate conduit.
It is one object of this invention to provide an improved containment system.
It is another object of this invention to provide an improved fitting for use in a containment system.
Still another object of the present invention is to provide an improved fitting that is inexpensive to produce and easy to install.
It is another object of this invention to provide a secondarily-contained piping system that is capable of containing and/or distributing secondary substances, without necessarily including a separate conduit.
It is still another object of this invention to provide a secondarily-contained hydrocarbon fuel piping system that is capable of containing and/or distributing vapor.
It is yet another object of this invention to provide fittings for use with a secondarily-contained piping system that is capable of containing and/or distributing secondary substances.
According to one embodiment of the present invention, a fitting for conduit comprises a body and an acceptor. The body has a wall and a throughbore. Meanwhile, the acceptor is disposed along the wall and is capable of providing a sealing interface between the throughbore and the conduit.
Preferably, the acceptor comprises a space defined between an interior surface of the wall of the body and a lip connected to the body. More preferably, the lip is a substantially rigid sleeve arranged generally parallel to the interior surface of the wall of the body. In preferred fittings according to this embodiment, an end of the sleeve is chamfered. According to another preferred embodiment of the invention, the lip and body are integrally connected.
In yet another preferred embodiment of the present invention, the fitting further includes a clasp capable of securing a portion of the conduit to the body. Preferably, a first end of the body defines an opening capable of receiving the conduit, and the clasp is capable of securing a portion of the conduit adjacent to the opening to the body. Furthermore, a preferred fitting further includes a protrusion extending from the body, wherein the clasp is adapted to receive the protrusion. In preferred fittings according to this embodiment, the protrusion is disposed on an exterior surface of the wall and is substantially adjacent a first end of the wall.
Preferably, the clasp includes opposing, generally semi-circular halves. In embodiments including a clasp, a preferred fitting further includes a fastener for securing the clasp to the body. Moreover, preferred clasps include a first portion adapted to be received in a groove on the conduit.
In a preferred embodiment, the fitting further includes a seal capable of cooperating with the conduit and the acceptor to form the sealing interface. Preferably, the seal is capable of cooperating with a groove on the conduit to form the sealing interface. More preferably, the seal comprises a ring having a generally T-shaped conformation.
According to another preferred embodiment of the present invention, a second end of the body is adapted to cooperate with another fitting. Preferably, the second end of the body is threaded. Alternatively, a second end of the body is connected to a second fitting, the throughbores of the first and second fittings being in fluid communication. In yet another alternative embodiment, a second end of the body is connected to a plurality of fittings, the throughbores of the plurality of fittings being in fluid communication. In addition, a preferred fitting according to the present invention has at least a portion of an external surface of the body adapted to be received by a wrench.
In another embodiment of the present invention, a containment system comprises a conduit, a fitting, and a sealing interface. The conduit has at least one wall and a flow passage. The fitting includes a body and an acceptor. The body has a wall and a throughbore. Meanwhile, the acceptor is disposed along the wall of the body and receives a portion of the at least one wall of the conduit. The sealing interface is between the throughbore and the flow passage.
Preferably, the acceptor comprises a space defined between an interior surface of the wall of the body and a lip connected to the body. More preferably, the lip comprises material having a first coefficient of thermal expansion and the at least one wall of the conduit comprises material having a second coefficient of thermal expansion. The first coefficient of thermal expansion is preferably less than the second coefficient of thermal expansion.
In yet another embodiment of the present invention, a secondary containment system comprises a primary conduit, a secondary conduit, a fitting comprising a body and an acceptor, and a sealing interface. The primary conduit is capable of containing hydrocarbon fuel. The secondary conduit generally surrounds at least a portion of the primary conduit and has a flow passage and a wall with a generally corrugated external surface.
The body of the fitting has a wall and a throughbore capable of allowing the primary conduit and the flow passage to communicate therethrough. The acceptor is disposed along the wall and receives a portion of the wall of the secondary conduit. The sealing interface is between the throughbore and the flow passage.
Preferably, the acceptor comprises a space defined between an interior surface of the wall of the body and a substantially rigid lip connected to the body, wherein the lip comprises a sleeve arranged substantially parallel to the interior surface of the wall of the body. More preferably, a first end of the body defines an opening capable of receiving the secondary conduit. According to this embodiment, the secondary containment system further includes a clasp securing a portion of the secondary conduit adjacent the opening to the body, and a protrusion extending from the body. The clasp receives the protrusion, and a first portion of the clasp is received in a groove on the generally corrugated external surface of the wall of the secondary conduit. Furthermore, a preferred secondary containment system according to this embodiment includes a seal cooperating with a groove on the generally corrugated external surface of the wall of the secondary conduit to form the sealing interface, and the seal comprises a ring having a generally T-shaped conformation.
Still other aspects of the present invention will become apparent to those skilled in this art from the following description wherein there is shown and described various embodiments of this invention, simply by way of illustration. As will be realized, the invention is capable of other different aspects and embodiments without departing from the scope of the invention. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not as restrictive in nature.